John Gruber pens an excellent post on pixel resolution, and surmises how the new Apple MacBook Pro with retina display is the best computer Apple’s ever made:

Today’s pre-retina Mac displays are excellent, especially when judged by historical standards. Brighter, more vibrant colors, and — again, by historical standards — smaller, sharper pixels. A regular 15-inch MacBook Pro ships with a 1440 × 900 pixel display at about 110 pixels per inch, and can be configured with a 1680 × 1050 display at about 130 pixels per inch. Both the 11- and 13-inch MacBooks Air sport resolutions of roughly 130 pixels per inch. Far beneath the retina threshold, but much nicer than our sub-100-PPI displays of the 90s, to say nothing of the mere 72 PPI display on the original 1984 Macintosh.

But we went from 72 PPI in 1984 to 132 PPI in 2012 gradually — a few more pixels per inch every few years. Along the way there was never a moment of celebration, no single great leap forward pixel-density-wise. Even the shift from bulky CRTs to slim flatscreen LCDs didn’t bring about a significant upgrade in terms of pixel size.

But now this. The 15-inch MacBook Pro With Retina Display. This is a boom. A revolution in resolution. The display I’ve been craving ever since I first saw high-resolution laser printer output.

In the footnotes, John Gruber notes that the 15-inch MacBook Pro puts him in a dilemma: it’s too big a laptop to lug around as a travel companion. I’m in the same position. I played around with the retina MacBook Pro when it came out, but I much prefer my 13-inch non-retina MacBook Air for its weight and portability. But when Apple releases the 13-inch retina MacBook Air, I am going to have a hard time holding out upgrading…